1. Field of the Invention
Embodiments of the invention generally relate to semiconductor and other electronic device processing, and more particularly, to an improved method for treating the surfaces of a processing chamber and a substrate therein prior to a vapor deposition process.
2. Description of the Related Art
The electronic device industry and the semiconductor industry continue to strive for larger production yields while increasing the uniformity of layers deposited on substrates having increasingly larger surface areas. These same factors in combination with new materials also provide higher integration of circuits per unit area on the substrate. The need for greater uniformity, deposition rate, and process control regarding layer characteristics rises as the desire for an increased circuit integration. Formation of tantalum-containing layers, such as tantalum, tantalum nitride, and tantalum silicon nitride, in multi-level integrated circuits poses many challenges to process control, particularly with respect to contact formation.
Barrier layers formed from sputtered tantalum and reactive sputtered tantalum nitride have demonstrated properties suitable for use to control copper diffusion. Exemplary properties include high conductivity, high thermal stability and resistance to diffusion of foreign atoms. Both physical vapor deposition (PVD) and atomic layer deposition (ALD) processes are used to deposit tantalum or tantalum nitride in features of small size (e.g., about 90 nm wide) and high aspect ratios of about 5:1. However, it is believed that PVD processes may have reached a limit at this size and aspect ratio, while ALD processes suffer other problems.
Common problems encountered during ALD processes include the lack of stability for the deposition rate and the non-uniformity performance after multiple runs are completed within the same ALD processing chamber. The aging of the the processing chamber, including the process kit within, is a function of the deposition frequencey and the type of deposited film on the inner surfaces of the processing chamber. The deposited film on the inner surfaces of the processing chamber significantly affects the deposition characteristics of ALD processes due to introduction of secondary reactions. The secondary reactions result in a drift of the deposition rate and the non-uniformity performance with increasing number of substrates processed within the ALD chamber. Also, deposited films on the inner surfaces of the processing chamber may peel to form particulates, which end up contaminating the substrate surface.
Therefore, there is a need for increasing the stability of the deposition rate and the uniformity of deposited materials on a substrate during a vapor deposition process, as well as a need to reduce or elimante contaminants within the processing chamber.